a. Field of the Invention
The present invention pertains generally to electric vehicles and specifically to an electric powered trailer to push a bicycle or push scooter.
b. Description of the Background
Traditionally, human muscle power has propelled bicycles and push scooters by way of pedaling or pushing. Steep inclines and heavy loads require more muscle power, as well as reduce speed, limiting the performance of the bicycle or push scooter. Various types of motors have been mounted on bicycles and push scooters. However, mounting a motor on the bicycle or push scooter frame compromises power and performance by adding weight to the bicycle or push scooter. In addition, the added weight makes the bicycle or push scooter impractical as a human-powered vehicle. Existing motorized bicycles and push scooters also offer limited cargo hauling capabilities because of their small size, limited weight carrying capabilities, and difficulty balancing large loads.
A crude electric bicycle pusher trailer was constructed prior to 1981 by David A. Ferre. Ferre""s trailer is described in page 189 in the Complete Book of Electric Vehicles, Sheldon R. Shaket, Copyright 1981. Ferre""s trailer did not have a speed controller or an efficient electric motor drive train. The trailer attached high up on the base of the seat, which would cause unstable power conditions. Because of the Ferre""s crude power on off switch control of the power, it was recommended that the operator start pedaling the bicycle before engaging the motor.
It would therefore be valuable to provide a method of assisting a bicycle or push scooter that was easily controllable, had large carrying capacity while still being stable, was easily detachable, and did not impart forces onto the bicycle or scooter that were unnatural or difficult for the operator.
The present invention overcomes the disadvantages and limitations of the prior art by providing a two wheeled trailer that pushes a bicycle or scooter from behind. The trailer mounts to a bicycle near the rear axle of the bicycle using a three axis connector. The connector may include a quick disconnect feature so that the trailer may be removed easily and quickly. The trailer contains a controller, batteries, and a motor that powers one of the two wheels of the trailer. The trailer is controlled by a potentiometer mounted on the handlebars and operated by a rider""s thumb or other finger.
The items mounted in the trailer may be mounted very low so that the center of gravity is close to the ground, which improves the handling characteristics. Further, the three axis mount that is attached to the bicycle is done so very near the rear wheel, which is advantageous so that the forces exerted by the trailer onto the bicycle are felt by the rider to be natural and anticipated. The trailer has the advantage that the rider may elect to pedal the bicycle for enjoyment, to assist the trailer, or to travel without the assistance of the trailer.
The trailer has the ability to carry more weight in the form of batteries, motor, and drivetrain components than could be placed on a bicycle frame, allowing the present invention to have greatly increased range and power over such frame mounted options. The trailer may further be outfitted with a cargo container or a flat area whereby large, heavy objects may be transported.
The present invention may therefore comprise a device for propelling a two wheeled vehicle comprising: a driven wheel and a free wheel, the driven wheel and the free wheel being aligned axially to each other and rotatably mounted to a frame; the driven wheel attached to an electrical motor; the electrical motor in electrical communication with a controller; the controller in electrical communication with at least one battery and in further communication with a potentiometer; and the device being attached to the vehicle near the rear axle of the vehicle with a connector that allows three degrees of axial rotation.
The present invention may further comprise a trailer for pushing a two wheeled vehicle comprising: a first wheel and a second wheel; the first wheel being in mechanical communication with a motor and the second wheel being free wheeling; a controller in electrical communication with at least one battery and the motor; a potentiometer in electrical communication with the controller; a connector attached to the vehicle near the rear axle of the vehicle; said connector allowing three orthogonal axes of rotation between the vehicle and the trailer; and the first wheel being offset from a longitudinal centerline of the vehicle.
The present invention may further comprise a method of constructing a two wheeled vehicle using a powered trailer comprising: fabricating a frame, the frame having a hitch that has three orthogonal axes of rotation and being adapted to clamp near the rear axle of a two wheeled vehicle; mounting a first wheel and a second wheel to the frame, the wheels being aligned axially and rotatably attached to the frame; mounting an electric motor to the frame; connecting the motor to the first wheel such that the first wheel is driven by the motor; mounting a controller to the frame; mounting at least one battery to the frame; electrically connecting the motor to the controller; the controller being connected to the battery; and electrically connecting a potentiometer to the controller.
The advantages of the present invention are a low cost and efficient device to assist a rider of a two wheeled vehicle such as a scooter or bicycle. The single attachment point near the rear axle imparts the minimum opposing force that may seem unnatural and unexpected to the novice rider of the device. The two wheeled design may accommodate large cargoes. The simple potentiometer input offers the rider excellent control of the vehicle, while the three axis swivel mount allows the rider to operate the powered vehicle with a similar feel and response as a conventional, unpowered version.